iron Presence of trace elements, irradiation and iron impurities give the gem amethyst its purplish color!
Answer:
D Cobalt
Explanation:
The volume of the sphere is 40 -25 = 15 cm^3
Density = mass/volume = 133 gm / 15 cm^3 = 8.87 gm/cm^3
which corresponds to Cobalt from the chart
2n² rule:
This rule is used to determine number of electrons in particular shell.
n=1 means K shell
n=2 means L shell
n=3 means M shell
n=4means N shell
The first K shell can hold upto 2 electrons, L shell can hold up to 8, third M shell can hold up to 18and the fourth N shell can hold upto 32 electrons. This rule of arrangement of electrons according to the shell is known 2n2 rule where n means number of shell.
For example: There is one proton in the nucleus of hydrogen atom, which moves in K shell path. It has no neutron.
Democritus (460-370 BC) was a Greek philosopher who theorized that all matter could be reduced to particles that could not be divided, which he described as “atomos.”
John Dalton (1766-1844) Proposed the atomic theory.
Answer:
D
Explanation:
Everything in this world is made up of particles of matter
